feat(notification-service): replace Teams with Telegram notifications

Replace Microsoft Teams webhook integration with Telegram Bot API.
Remove Teams-specific models (MessageCard, Section, Fact) and service.
Add TelegramNotificationService using TELEGRAM_BOT_TOKEN and TELEGRAM_CHAT_ID
environment variables.

Assisted-by: Claude:claude-sonnet-4-6

notification_service/pom.xml

@@ -15,7 +15,7 @@
   <artifactId>notification-service</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>notification-service</name>
-  <description>Air quality alert notifications via Microsoft Teams</description>
+  <description>Air quality alert notifications via Telegram</description>
 
   <properties>
     <java.version>17</java.version>
@@ -32,6 +32,12 @@
       <optional>true</optional>
     </dependency>
 
+    <dependency>
+      <groupId>me.paulschwarz</groupId>
+      <artifactId>spring-dotenv</artifactId>
+      <version>4.0.0</version>
+    </dependency>
+
     <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-test</artifactId>

notification_service/src/main/java/ch/hesso/pi/notification/config/NotificationProperties.java

@@ -7,20 +7,24 @@ import org.springframework.context.annotation.Configuration;
 @ConfigurationProperties(prefix = "notification")
 public class NotificationProperties {
 
-    private Teams teams = new Teams();
+    private Telegram telegram = new Telegram();
     private AirQuality airQuality = new AirQuality();
 
-    public Teams getTeams() { return teams; }
+    public Telegram getTelegram() { return telegram; }
-    public void setTeams(Teams teams) { this.teams = teams; }
+    public void setTelegram(Telegram telegram) { this.telegram = telegram; }
 
     public AirQuality getAirQuality() { return airQuality; }
     public void setAirQuality(AirQuality airQuality) { this.airQuality = airQuality; }
 
-    public static class Teams {
+    public static class Telegram {
-        private String webhookUrl;
+        private String botToken;
+        private String chatId;
 
-        public String getWebhookUrl() { return webhookUrl; }
+        public String getBotToken() { return botToken; }
-        public void setWebhookUrl(String webhookUrl) { this.webhookUrl = webhookUrl; }
+        public void setBotToken(String botToken) { this.botToken = botToken; }
+
+        public String getChatId() { return chatId; }
+        public void setChatId(String chatId) { this.chatId = chatId; }
     }
 
     public static class AirQuality {

notification_service/src/main/java/ch/hesso/pi/notification/model/teams/Fact.java

@@ -1,3 +0,0 @@
-package ch.hesso.pi.notification.model.teams;
-
-public record Fact(String name, String value) {}

notification_service/src/main/java/ch/hesso/pi/notification/model/teams/MessageCard.java

@@ -1,30 +0,0 @@
-package ch.hesso.pi.notification.model.teams;
-
-import com.fasterxml.jackson.annotation.JsonProperty;
-
-import java.util.List;
-
-/**
- * Office 365 Connector Card (MessageCard) payload for Teams incoming webhooks.
- * Spec: https://learn.microsoft.com/en-us/outlook/actionable-messages/message-card-reference
- *
- * Adaptive Cards require a Bot Framework registration; this format works with
- * any incoming webhook URL without extra infrastructure.
- */
-public record MessageCard(
-
-    @JsonProperty("@type")
-    String type,
-
-    @JsonProperty("@context")
-    String context,
-
-    String themeColor,
-    String summary,
-    String title,
-    String text,
-    List<Section> sections
-) {
-    public static final String TYPE    = "MessageCard";
-    public static final String CONTEXT = "https://schema.org/extensions";
-}

notification_service/src/main/java/ch/hesso/pi/notification/model/teams/Section.java

@@ -1,14 +0,0 @@
-package ch.hesso.pi.notification.model.teams;
-
-import com.fasterxml.jackson.annotation.JsonInclude;
-
-import java.util.List;
-
-@JsonInclude(JsonInclude.Include.NON_NULL)
-public record Section(
-    String      activityTitle,
-    String      activitySubtitle,
-    String      activityImage,
-    List<Fact>  facts,
-    boolean     markdown
-) {}

notification_service/src/main/java/ch/hesso/pi/notification/scheduler/AirQualityScheduler.java

@@ -4,7 +4,7 @@ import ch.hesso.pi.notification.config.NotificationProperties;
 import ch.hesso.pi.notification.model.Co2Level;
 import ch.hesso.pi.notification.model.SensorReading;
 import ch.hesso.pi.notification.service.AirQualityService;
-import ch.hesso.pi.notification.service.TeamsNotificationService;
+import ch.hesso.pi.notification.service.TelegramNotificationService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.scheduling.annotation.Scheduled;
@@ -24,15 +24,15 @@ public class AirQualityScheduler {
         new SensorReading("B1", "Salle B1",  780, 21.0, 42, "closed", Instant.now())
     );
 
-    private final AirQualityService        airQualityService;
+    private final AirQualityService           airQualityService;
-    private final TeamsNotificationService  teamsService;
+    private final TelegramNotificationService telegramService;
-    private final NotificationProperties    props;
+    private final NotificationProperties      props;
 
     public AirQualityScheduler(AirQualityService airQualityService,
-                                TeamsNotificationService teamsService,
+                                TelegramNotificationService telegramService,
                                 NotificationProperties props) {
         this.airQualityService = airQualityService;
-        this.teamsService      = teamsService;
+        this.telegramService   = telegramService;
         this.props             = props;
     }
 
@@ -55,7 +55,7 @@ public class AirQualityScheduler {
             Co2Level level = airQualityService.resolveLevel(reading.co2());
             if (airQualityService.isAlertable(level)) {
                 log.info("Alertable reading: room={} co2={} level={}", reading.roomId(), reading.co2(), level);
-                teamsService.sendAlert(reading, level);
+                telegramService.sendAlert(reading, level);
             }
         }
     }

notification_service/src/main/java/ch/hesso/pi/notification/service/TeamsNotificationService.java

@@ -1,92 +0,0 @@
-package ch.hesso.pi.notification.service;
-
-import ch.hesso.pi.notification.config.NotificationProperties;
-import ch.hesso.pi.notification.model.Co2Level;
-import ch.hesso.pi.notification.model.SensorReading;
-import ch.hesso.pi.notification.model.teams.Fact;
-import ch.hesso.pi.notification.model.teams.MessageCard;
-import ch.hesso.pi.notification.model.teams.Section;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.springframework.http.MediaType;
-import org.springframework.stereotype.Service;
-import org.springframework.util.StringUtils;
-import org.springframework.web.client.RestClient;
-import org.springframework.web.client.RestClientException;
-
-import java.time.ZoneId;
-import java.time.format.DateTimeFormatter;
-import java.util.List;
-
-@Service
-public class TeamsNotificationService {
-
-    private static final Logger log = LoggerFactory.getLogger(TeamsNotificationService.class);
-    private static final DateTimeFormatter TIME_FMT =
-        DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneId.systemDefault());
-
-    private final RestClient restClient;
-    private final NotificationProperties props;
-
-    public TeamsNotificationService(RestClient restClient, NotificationProperties props) {
-        this.restClient = restClient;
-        this.props      = props;
-    }
-
-    /**
-     * Builds and sends a MessageCard to the configured Teams webhook.
-     * Does nothing if the webhook URL is not configured.
-     */
-    public void sendAlert(SensorReading reading, Co2Level level) {
-        String webhookUrl = props.getTeams().getWebhookUrl();
-        if (!StringUtils.hasText(webhookUrl)) {
-            log.warn("Teams webhook URL not configured — skipping alert for room {}", reading.roomId());
-            return;
-        }
-
-        MessageCard card = buildCard(reading, level);
-
-        try {
-            restClient.post()
-                .uri(webhookUrl)
-                .contentType(MediaType.APPLICATION_JSON)
-                .body(card)
-                .retrieve()
-                .toBodilessEntity();
-
-            log.info("Alert sent for room {} — {} ({} ppm)", reading.roomId(), level.getLabel(), reading.co2());
-        } catch (RestClientException e) {
-            log.error("Failed to send Teams alert for room {}: {}", reading.roomId(), e.getMessage());
-        }
-    }
-
-    private MessageCard buildCard(SensorReading reading, Co2Level level) {
-        String timestamp = reading.timestamp() != null
-            ? TIME_FMT.format(reading.timestamp())
-            : "—";
-
-        Section section = new Section(
-            level.getLabel() + " — " + reading.roomName(),
-            "Detected at " + timestamp,
-            null,
-            List.of(
-                new Fact("Room",        reading.roomName()),
-                new Fact("CO₂",         reading.co2() + " ppm"),
-                new Fact("Temperature", reading.temperature() + " °C"),
-                new Fact("Humidity",    reading.humidity() + " %"),
-                new Fact("Windows",     reading.windowState())
-            ),
-            true
-        );
-
-        return new MessageCard(
-            MessageCard.TYPE,
-            MessageCard.CONTEXT,
-            level.getThemeColorHex(),
-            "Air quality alert: " + reading.roomName(),
-            "🌬️ Air Quality Alert",
-            null,
-            List.of(section)
-        );
-    }
-}

notification_service/src/main/java/ch/hesso/pi/notification/service/TelegramNotificationService.java

@@ -0,0 +1,81 @@
+package ch.hesso.pi.notification.service;
+
+import ch.hesso.pi.notification.config.NotificationProperties;
+import ch.hesso.pi.notification.model.Co2Level;
+import ch.hesso.pi.notification.model.SensorReading;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Service;
+import org.springframework.util.StringUtils;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.client.RestClientException;
+
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Map;
+
+@Service
+public class TelegramNotificationService {
+
+    private static final Logger log = LoggerFactory.getLogger(TelegramNotificationService.class);
+    private static final DateTimeFormatter TIME_FMT =
+        DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneId.systemDefault());
+
+    private final RestClient restClient;
+    private final NotificationProperties props;
+
+    public TelegramNotificationService(RestClient restClient, NotificationProperties props) {
+        this.restClient = restClient;
+        this.props      = props;
+    }
+
+    public void sendAlert(SensorReading reading, Co2Level level) {
+        String token  = props.getTelegram().getBotToken();
+        String chatId = props.getTelegram().getChatId();
+
+        if (!StringUtils.hasText(token) || !StringUtils.hasText(chatId)) {
+            log.warn("Telegram credentials not configured — skipping alert for room {}", reading.roomId());
+            return;
+        }
+
+        String url  = "https://api.telegram.org/bot" + token + "/sendMessage";
+        String text = buildMessage(reading, level);
+
+        try {
+            restClient.post()
+                .uri(url)
+                .contentType(MediaType.APPLICATION_JSON)
+                .body(Map.of("chat_id", chatId, "text", text, "parse_mode", "HTML"))
+                .retrieve()
+                .toBodilessEntity();
+
+            log.info("Telegram alert sent for room {} — {} ({} ppm)", reading.roomId(), level.getLabel(), reading.co2());
+        } catch (RestClientException e) {
+            log.error("Failed to send Telegram alert for room {}: {}", reading.roomId(), e.getMessage());
+        }
+    }
+
+    private String buildMessage(SensorReading reading, Co2Level level) {
+        String timestamp = reading.timestamp() != null
+            ? TIME_FMT.format(reading.timestamp())
+            : "—";
+
+        return String.format(
+            "<b>%s — Air Quality Alert</b>\n\n" +
+            "<b>Room:</b> %s\n" +
+            "<b>CO₂:</b> %d ppm\n" +
+            "<b>Temperature:</b> %.1f °C\n" +
+            "<b>Humidity:</b> %d %%\n" +
+            "<b>Windows:</b> %s\n" +
+            "<b>Time:</b> %s",
+            level.getLabel(),
+            reading.roomName(),
+            reading.co2(),
+            reading.temperature(),
+            reading.humidity(),
+            reading.windowState(),
+            timestamp
+        );
+    }
+}

notification_service/src/main/resources/application.yml

@@ -3,8 +3,9 @@ spring:
     name: notification-service
 
 notification:
-  teams:
+  telegram:
-    webhook-url: ${TEAMS_WEBHOOK_URL:https://defaulta372f724c0b24ea0abfb0eb8c6f84e.40.environment.api.powerplatform.com:443/powerautomate/automations/direct/workflows/e661f41b50314eeebaccc123a0fcc129/triggers/manual/paths/invoke?api-version=1&sp=%2Ftriggers%2Fmanual%2Frun&sv=1.0&sig=0L78wU0kY2jjnXUwehf6lkDnA61vQOD4SuTHcRsdOX8}
+    bot-token: ${TELEGRAM_BOT_TOKEN}
+    chat-id: ${TELEGRAM_CHAT_ID}
   air-quality:
     api-url: ${AIR_QUALITY_API_URL:http://localhost:8080}
     poll-interval-ms: ${POLL_INTERVAL_MS:60000}

notification_service/src/test/java/ch/hesso/pi/notification/NotificationServiceApplicationTests.java

@@ -6,7 +6,8 @@ import org.springframework.test.context.TestPropertySource;
 
 @SpringBootTest
 @TestPropertySource(properties = {
-    "notification.teams.webhook-url=http://localhost:9999/test",
+    "notification.telegram.bot-token=test-token",
+    "notification.telegram.chat-id=123456789",
     "notification.air-quality.api-url=http://localhost:9998"
 })
 class NotificationServiceApplicationTests {